Transseptal puncture apparatus

Abstract

Devices and methods for performing a transeptal puncture procedure are described. In certain embodiments, the device includes a blunt outer needle, and a second inner needle disposed longitudinally through the lumen of the outer needle, wherein the inner needle is flexible, e.g., has a flexible portion and/or a bend or other non-traumatic conformation at its tip.

1. A device for puncturing the atrial septum of a patient, comprising:
 an outer needle comprising a blunt distal end and a lumen longitudinally disposed substantially therethrough; 
 a solid inner needle axially disposed in the lumen of the outer needle and moveable beyond the distal end of the outer needle, the solid inner needle comprising a first material and further comprising:
 a proximal portion; 
 a distal portion having a proximal section that is more flexible than the proximal portion, the distal portion increasing in flexibility from the proximal section to a distal end and includes a sharp tip configured to pierce the atrial septum; and 
 an intermediate portion that is substantially straight, is more flexible than the proximal section of the distal portion, and has a circumference substantially equal to or greater 
 than that of the proximal section of the distal portion, wherein the intermediate portion includes a second material that is different from the first material. 
 
 
     
     
       2. The device of  claim 1 , wherein the intermediate portion has a longitudinal length ranging from about 0.5 mm to about 30 mm. 
     
     
       3. The device of  claim 1  wherein the distal portion of the inner needle comprises a distal tip portion that deviates from the linear path of the needle when not constrained within the lumen of the outer needle. 
     
     
       4. The device of  claim 3 , wherein the distal portion, when residing outside the outer needle, is capable for forming a shape selected from the group consisting of a helix, a curve, a cork screw, and a hook. 
     
     
       5. The device of  claim 1 , wherein the first material is nitinol. 
     
     
       6. The device of  claim 1 , wherein the second material includes a polymer. 
     
     
       7. The device of  claim 1 , wherein the intermediate portion includes at least one of a slit, a groove, a cut-away, a notch, and a dimple. 
     
     
       8. The device of  claim 1 , wherein the intermediate portion has a cross-sectional area that is smaller than the cross-sectional area of the proximal portion. 
     
     
       9. The device of  claim 1 , wherein the distal portion has sufficient stiffness to penetrate the atrial septum when the distal portion substantially resides within the outer needle and has insufficient stiffness to penetrate cardiac tissue when the distal portion substantially resides outside the outer needle. 
     
     
       10. The device of  claim 1 , wherein the distal portion has a longitudinal length ranging from about 5 mm to about 30 mm. 
     
     
       11. The device of  claim 10 , wherein the distal portion has a longitudinal length ranging from about 10 mm to about 20 mm. 
     
     
       12. The device of  claim 1 , further including one or more flexible members configured to contact the atrial septum, wherein at least one of the one or more flexible members is configured to reside within a lumen in a compressed state and configured to reside in an expanded state when outside the lumen. 
     
     
       13. The device of  claim 12 , wherein at least one of the flexible members includes a shape selected from at least one of a hexagon, a curve, a loop, a planar section, a coil, and a spiral. 
     
     
       14. The device of  claim 12 , wherein at least one of the flexible members is connected to at least one of the outer needle and the solid inner needle. 
     
     
       15. The device of  claim 12 , wherein at least one of the flexible members is connected to an elongate member, wherein the elongate member includes a lumen configured to receive the outer needle. 
     
     
       16. The device of  claim 12 , wherein at least one of the flexible members includes nitinol. 
     
     
       17. The device of  claim 12 , wherein at least one of the flexible members is configured to contact a first side and a second side of the atrial septum. 
     
     
       18. The device of  claim 12 , wherein at least one of the flexible members is configured to reside within a hole in the atrial septum. 
     
     
       19. The device of  claim 1 , wherein the distal portion has a generally conical shape that extends from the proximal end to the distal end of the distal portion. 
     
     
       20. The device of  claim 1 , wherein the intermediate portion has a generally uniform cross-section along a longitudinal axis of the intermediate portion. 
     
     
       21. The device of  claim 1 , wherein the device is moveable between a piercing configuration in which at least part of the distal portion of the solid needle is located within the lumen of the outer needle and a non-piercing configuration wherein at least part of the intermediate portion is located outside the lumen of the outer needle. 
     
     
       22. A device for puncturing the atrial septum of a patient, comprising:
 an outer needle comprising a blunt distal end and a lumen longitudinally disposed substantially therethrough; and 
 a solid inner needle axially disposed in the lumen of the outer needle and moveable beyond the distal end of the outer needle, the solid inner needle comprising a first material and further comprising:
 a proximal portion having a distal end; 
 an intermediate portion having a proximal shoulder and a distal shoulder and comprising a second material that is different from the first material; and 
 a distal portion having a proximal end abutting the distal shoulder and a sharp tip configured to pierce the atrial septum, the proximal end of the distal portion having a circumference substantially equal to or less than that of the intermediate portion; 
 
 wherein the flexibility of the intermediate portion from the proximal shoulder to the distal shoulder is greater than the flexibility of the proximal end of the distal portion, and the flexibility of the proximal end of the distal portion is greater than the flexibility of the proximal portion, and wherein the distal portion increases in flexibility from the proximal end of the distal portion to the sharp tip and includes a taper extending to the sharp tip.